Arms Race Between Plants and Animals: Biotransformation System

Abstract

Interactions between plants and herbivores are of major importance in natural ecosystems. The phytochemical co-evolution theory suggests that plant secondary metabolites are likely the most important mediators of plant-herbivore interactions, although their primary cause for production is the shielding effect against adverse environmental triggers. According to this theory, both plants and insect herbivores generate selective forces that lead to the evolution of plant defense (i.e., plant secondary metabolites, PSM) and herbivore offense (i.e., detoxification ability) in a so-called co-evolutionary arms race. These chemicals, although not required for primary plant metabolic processes such as respiration or growth, have been extensively recognized for their role in plant defense against herbivore and pathogen attack (Bidart-Bouzat and Imeh-Nathaniel 2008). There is still some concern, though, as to whether or not the primary reason for the production of PSM is protection from photodamage rather than from herbivory. Nevertheless, there is no doubt that these metabolites also function as food allelochemicals, that is plant defense.